868  
FXUS65 KBYZ 211803  
AFDBYZ  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE BILLINGS MT  
1203 PM MDT SAT SEP 21 2019  
   
UPDATE
 
 
UPDATED FORECAST TO DROP THE WINTER STORM WARNING FOR THE  
BEARTOOTH/ABSAROKA MOUNTAINS. CHAMBERS  
 

 
   
SHORT TERM...VALID FOR TDY AND SUN
 
 
THE TROUGH AXIS IS NOW PRETTY MUCH LOCATED FROM BILLINGS DOWN TO  
TO THE BIG HORN MOUNTAINS. THE DRY SLOT THAT KEPT SOME OF THE RAIN  
OUT OF THE CENTRAL ZONES AROUND BILLINGS LAST EVENING HAS PUSHED  
TO THE EAST, NOW CLEARING THE RAINFALL OUT OF ROSEBUD COUNTY EAST  
INTO THE DAKOTAS. THE WRAP AROUND PRECIPITATION OVER THE WEST WILL  
OVERSPREAD THE AREA THROUGH THE MORNING, BEFORE STARTING TO MOVE  
OUT DURING THE AFTERNOON. DURING THE AFTERNOON EXPECTING THE  
ACTIVITY TO BECOME MORE SCATTERED, HIT AND MISS THAN THE  
WIDESPREAD PRECIP THAT HAS BEEN OCCURING. ADDITIONAL RAINFALL  
THROUGH THE DAY TODAY WILL BE IN THE QUARTER TO HALF INCH RANGE,  
WITH AMOUNTS CLOSER TO THREE-QUARTERS OF AN INCH TOWARDS MILES  
CITY AND BAKER AS THE HEAVY PRECIP WILL SPREAD THAT WAY AND REMAIN  
THERE THROUGH MUCH OF THE DAY. THE BEARTOOTH/ABSAROKA MOUNTAINS  
WILL SEE ADDITIONAL 4 TO 8 INCHES OF SNOW TODAY, SO WILL KEEP THE  
WINTER STORM WARNING GOING.  
 
NORTHWEST WINDS STILL EXPECTED TO INCREASE DURING THE DAY AS THE  
SURFACE LOW TIGHTENS THE PRESSURE GRADIENT. WINDS STILL LOOK TO BE  
15 TO 20 MPH WITH GUSTS 20 TO 30 MPH, WITH THE STRONGEST IN  
SOUTHEAST MONTANA NEARER TO THE TRACK OF THE LOW. WITH CLOUD COVER  
REMAINING FOR MOST OF THE DAY, TEMPERATURES WILL REMAIN BELOW  
NORMAL, WITH HIGHS ONLY IN THE 60S.  
 
SUNDAY WILL BE A WARM DAY AS HEIGHTS WILL BE RISING. HIGHS SHOULD  
BE NEARING NORMALS, UP INTO THE 70S. REIMER  
   
LONG TERM...VALID FOR MON...TUE...WED...THU...FRI
 
 
NORTHWEST FLOW ALOFT WILL DOMINATE THE WEATHER PATTERN FOR THE  
FIRST TWO DAYS OF THE LONG TERM. UNIDIRECTIONAL NORTHWEST FLOW  
LOOKS TO EXIST THROUGH THE MIXED LAYER ON TUESDAY, AND STRONG  
MOMENTUM TRANSFER AND LOW-LEVEL LAPSE RATES WILL BRING ABOUT GUSTY  
CONDITIONS AT, NORTH, AND WEST OF BILLINGS THROUGHOUT THE DAY. AN  
UPPER RIDGE WILL MOVE OVER THE AREA THROUGH WEDNESDAY, KEEPING  
RELATIVELY CALM AND DRY CONDITIONS.  
 
BEGINNING THURSDAY, A DEEP UPPER TROUGH LOOKS TO SET UP OVER THE  
WESTERN U.S. COAST, AND PERSIST THERE THROUGH THE WEEKEND. THIS  
ANOMALOUS WEATHER PATTERN WILL HELP TO COOL CONDITIONS OFF AND  
BRING MULTIPLE ROUNDS OF PRECIPITATION. HOWEVER, MUCH UNCERTAINTY  
EXISTS WITH THIS SYSTEM, IN-PART DUE TO A DRIVING FORCE BEING  
TYPHOON TAPAH IN THE WESTERN PACIFIC OCEAN. TEMPERATURES HIGHS  
HAVE UP TO A 30 DEGREE DIFFERENCE, AND LARGE DIFFERENCES IN 500 MB  
HEIGHTS EXIST AS WELL. HOWEVER, IT DOES SEEM FAIRLY CONSISTENT  
THAT THE WEEKEND WILL COOL OFF FROM ITS MID WEEK TEMPERATURES, AND  
BE WET.  
 
MID WEEK TEMPERATURES WILL RANGE FROM THE UPPER 60S TO LOW 70S,  
WITH WEEKEND TEMPERATURES COOLING OFF TO THE 50S.  
 
VERTZ  
 

 
   
AVIATION
 
 
CONDITIONS WILL RANGE FROM MVFR TO LIFR ACROSS THE AREA THROUGH  
THE MORNING IN RAIN SHOWERS. CONDITIONS WILL BEGIN TO IMPROVE  
AFTER 18Z AND SHOWERS MOVE FROM WEST TO EAST. BY 00Z, CONDITIONS  
SHOULD BE VFR TO MVFR, AND ALL SHOWERS SHOULD BE OUT OF THE AREA  
BY MIDNIGHT. EXPECT GUSTY WNW SURFACE WINDS, WITH GUSTS 20 TO 25  
KNOTS. WIDESPREAD MOUNTAIN OBSCURATIONS WILL DECREASE THIS  
AFTERNOON. REIMER/VERTZ  
 

 
   
PRELIMINARY POINT TEMP/POPS
 
 
TDY SUN MON TUE WED THU FRI  
-------------------------------------------------------  
BIL 063 046/072 049/078 052/073 047/065 044/062 041/054  
5/R 30/U 01/B 12/N 51/B 34/R 55/R  
LVM 060 040/069 042/074 047/067 041/063 040/059 036/052  
3/R 30/U 01/B 03/W 51/B 56/R 66/R  
HDN 062 044/072 046/076 049/072 044/063 042/062 040/055  
7/R 30/U 01/B 13/W 62/W 33/R 65/R  
MLS 063 045/071 048/078 051/070 044/063 044/062 041/056  
5/R 10/U 00/U 02/N 31/U 33/R 44/R  
4BQ 060 043/070 045/077 048/071 042/063 041/064 040/057  
7/R 20/U 00/B 12/B 51/U 22/R 54/R  
BHK 061 043/069 046/077 049/069 042/062 041/062 040/057  
7/R 10/U 00/U 01/N 31/U 33/R 33/R  
SHR 060 040/070 042/077 044/072 041/063 039/064 037/056  
6/R 30/U 01/B 13/B 71/B 22/R 64/R  
 

 
   
BYZ WATCHES/WARNINGS/ADVISORIES
 
 
MT...NONE.  
WY...NONE.  
 

 
 

 
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